The act of going from ass to vagina or removing one's penis from the asshole and placing it directly into the vagina without cleaning it first. Akin to ATM or "ass to mouth", the dirty kitty should be referred to as ATV.

My girlfriend was busting my balls one night so I decided to give her a Dirty Kitty. Yeah, I went full ATV on that bitch.

If you keep messing with me i'm going to ATV your wife next time I fuck her. Yeah, im going to Dirty Kitty that filthy slut, she deserves it.